code: def test_histogram_average_diplay(df_hist):
      "Test average & cumulative function of histogram"
  
      p_hist = df_hist.plot_bokeh.hist(
          y=["a", "b"],
          bins=np.arange(-4, 6.5, 0.5),
          normed=100,
          vertical_xlabel=True,
          ylabel="Share[%]",
          title="Normal distributions (normed)",
          show_average=True,
          xlim=(-4, 6),
          ylim=(0, 30),
          show_figure=False,
      )
  
      p_hist_cum = df_hist.plot_bokeh.hist(
          y=["a", "b"],
          bins=np.arange(-4, 6.5, 0.5),
          normed=100,
          cumulative=True,
          vertical_xlabel=True,
          ylabel="Share[%]",
          title="Normal distributions (normed & cumulative)",
          show_figure=False,
      )
  
      p_hist_cum_pandas_backend = df_hist.plot.hist(
          by=["a", "b"],
          bins=np.arange(-4, 6.5, 0.5),
          normed=100,
          cumulative=True,
          vertical_xlabel=True,
          ylabel="Share[%]",
          title="Normal distributions (normed & cumulative)",
          show_figure=False,
      )
  
      p_average = pandas_bokeh.plot_grid(
          [[p_hist, p_hist_cum, p_hist_cum_pandas_backend]],
          width=450,
          height=300,
          show_plot=False,
      )
  
      pandas_bokeh.output_file(
          os.path.join(
              DIRECTORY,
              "Plots",
              "Histogram_average_and_cumulative.html",
          )
      )
      pandas_bokeh.save(p_average)
  
imports: import os
  import numpy
  import pandas
  import pytest
  import pandas_bokeh
label_desc: Use image node_id 20 for calling a global function with example usage: test_histogram_average_diplay(df_hist) without return types